Distributor for evaporative condenser header or cooler header

ABSTRACT

A heat exchanger has heat exchange elements and an inlet header and an outlet header that fluidly communicate with the heat exchange elements. The inlet header has a fluid inlet. The heat exchange elements are connected to the inlet header along a length of the inlet header and are various distances from the fluid inlet. A distributor is located inside the inlet header, which distributor forms a perforated wall between the fluid inlet and the heat exchange elements. The distributor provides back pressure to incoming fluid into the inlet header, wherein the fluid is evenly distributed between the heat exchange elements.

FIELD OF THE INVENTION

The present invention relates to heat exchangers and more particularlyto evaporative condensers and coolers.

BACKGROUND OF THE INVENTION

Evaporative condensers are condensers where water is sprayed onto a heatexchanger to condense a gas into a liquid. For example, in arefrigeration system, a compressor compresses a heat exchange fluid,such as ammonia. The output of the compressor is hot, high pressureammonia gas. The gas is provided to a condenser, where it condenses intoa liquid. The liquid ammonia then passes through an expansion valve,where it drops in pressure and decreases in temperature to providerefrigeration.

In a conventional evaporative condenser, the heat exchanger for thefluid is a set of coils or tubes. The ammonia gas flows into a headerand then into the coils. Condensed or liquid ammonia flows out of thecoils to an outlet header.

In a cooler, the liquid disposes heat to the spraying water on theoutside of the coils. The cooler uses an input header for the liquid.

It is desirable to make improvements over conventional condensers. It isalso desirable to make improvements to conventional coolers.

SUMMARY OF THE INVENTION

A heat exchanger comprises inlet headers. The inlet header has a fluidinlet and an interior cavity. The outlet header has a fluid outlet. Heatexchange elements are coupled to and in fluid communication with theinlet and outlet headers. The heat exchange elements comprise first andsecond heat exchange elements. The first heat exchange element iscoupled to the inlet header at a first location. The second heatexchange element is coupled to the inlet header at a second location.The first location is closer to the fluid inlet than is the secondlocation. A distributor is located in the interior cavity of the inletheader between the fluid inlet and the heat exchange elements andextends between the first and second locations and the fluid inlet. Thedistributor causes back pressure for fluid entering the inlet headerfrom the fluid inlet.

In accordance with one aspect, the distributor comprises a perforatedwall.

In accordance with another aspect, the heat exchange elements comprisecoils.

In accordance with another aspect, the inlet header comprises a pipe andthe distributor comprises a perforated plate located in the pipe.

In accordance with another aspect, an evaporative condenser comprises acondenser unit. A water sprayer is located above the condenser unit. Afill section is located below the condenser unit. A basin located belowthe fill section. At least one fan for flowing air through the condenserunit and the fill section is provided. The condenser unit comprises aninlet header and an outlet header. The inlet header has a fluid inlet ata first location. The inlet header has heat exchange elements atlocations other than the first location. A distributor is in the inletheader between the first and other locations. The distributor appliesback pressure to incoming fluid in the inlet header.

In accordance with still another aspect, the distributor furthercomprises a perforated wall.

In accordance with still another aspect, the heat exchange elementscomprise coils.

In accordance with another aspect, the inlet header comprises a pipe andthe distributor comprises a perforated plate located in the pipe.

In accordance with still another aspect, the perforated plate is flat.In accordance with still another aspect, the perforated plate is curved.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an evaporative condenser.

FIG. 2 is a top plan view of a portion of the heat exchanger condenserand inlet header.

FIG. 3 is a cross-sectional view of the header of FIG. 2, taken alonglines III-III.

FIGS. 3A and FIG. 3B are cross-sectional views of the header, similar toFIG. 3, but of other embodiments.

FIG. 4 is a view of a distributor. FIG. 5 shows the distributor inaccordance with another embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The efficiency of any heat exchanger depends upon whether the incomingfluid is distributed evenly over all portions of the heat exchanger. Forexample, if the heat exchanger has coils arranged side by side, if thecenter coils receive more fluid than the other coils, then efficiencydeclines.

The heat exchanger described herein evenly distributes the incomingfluid throughout all portions thereof, thereby increasing efficiency.Although the heat exchanger can be a cooler, the particular applicationshown is in an evaporative cooler.

FIG. 1 shows an evaporative condenser 11. Sprayers 61 spray water onto aheat exchanger 13. A fan 15 draws air 17 through the wetted heatexchanger 13 to provide evaporative cooling and condensing of a fluid(typically from a gas into a liquid).

The evaporative condenser 11 has a housing 19. The heat exchanger 13 islocated in the housing. Below the heat exchanger is a fill or stuffingsection 21. The fill section 21 has layers that expose descending waterto air flow. The layers can be made of plastic, etc. Below the fillsection 21 is a basin 23 to catch the water. The housing also has aplenum 25 that communicates with the heat exchanger and the fillsection. The fan 15 draws air through the heat exchanger 13, in throughthe fill section 21, through demisters 27 or dehydrators, into theplenum 25 and out of the housing.

The heat exchanger 13 has heat exchange elements 31 that extend from aninlet header 33 to an outlet header 35. In the preferred embodiment, theheat exchanger elements 31 are coils, however the heat exchange elementscould be plates. Thus, there is a first set of coils 31A (see FIG. 2), asecond set of coils 31B, a third set of coils 31C and so on. Gas entersthe inlet header 33 and then the coils 31. Once in the coils, the gascondenses to a liquid. The liquid exits the coils 31 into the outletheader 35.

The inlet header 33 has an inlet pipe 37 (see FIG. 1) which delivers thegas to the inlet header 33. Likewise, the outlet header 35 has an outletpipe 39, which removes the liquid from the outlet header. Referring toFIGS. 2 and 3, the heat exchanger and inlet header are shown. In thepreferred embodiment, the inlet header 33 is a pipe with an interiorcavity 41 that extends between two ends 43. The header can be circularin transverse cross-section, rectangular, etc. The inlet pipe 37 and theheat exchange elements 31 all communicate with the interior cavity 41.The heat exchange elements are connected with the inlet header by way offeed pipe stubs 38. The ends 43 of the header are closed such as withcaps.

The inlet pipe 37 is typically located in the center between the ends43. The coils 31 are spaced out along the length of the header from oneend to the other end 43. Consequently, some coils are located closer tothe inlet pipe 37 than other coils. For example, centrally located coils31A-31D are closer to the inlet pipe than are end coils 31E, 31F, 31G,31H.

In order to evenly distribute the end feed fluid to all of the heatexchange coils, a distributor 51 is provided in the interior cavity 41of the inlet header 33. As shown in FIGS. 3 and 4, the distributor 51 isa plate with perforations 53. In the preferred embodiment, theperforations are circular holes; however the perforations could be anyshape such as slots, etc. The number and size of the perforations isdetermined relative to the flow of the incoming gas. The distributor 51applies a back pressure to the gas in the inlet header 33. This backpressure causes the gas to move from the central location of the inletheader out along the length of the inlet header toward the ends 43. Thisin turn promotes even distribution of the gas to the coils 31.

To assemble the inlet header 33, the inlet pipe 37 and feed pipes 38 areconnected to the header. With the interior cavity 41 of the headerexposed by way of an open end 43, the distributor plate 51 is insertedinto the header interior cavity. The length of the distributor plate isslightly less than the length of the header. The distributor plate ispositioned (vertically as shown in the orientation of FIG. 3) and thentacked or welded in place. The tacked points need only be at the endsand serve to immobilize the distributor inside the header. Then the endcaps can be put onto the header.

Because the plate is porous, there can be gaps between the plate and theheader. FIG. 5 shows another embodiment of the distributor 51A, havingopenings 53A in the sites adjacent to the header 33.

The distributor plate 51 is located between the inlet pipe 37 and thecoils 31 so that gas flowing into the header passes through thedistributor plate to flow into the coils. The distributor plate 51 canbe positioned along a vertical chord, as shown by solid lines in FIG. 3.The plate is positioned closer to the feed pipes than to the inlet pipe37. The plate 51 could be positioned closer to the inlet pipe 37, asshown by dashed lines in FIG. 3. The plate could also be positionedthrough the center of the header instead of along a chord.

FIG. 3 shows the distributor plate 51 as flat. The distributor plate 51need not be flat but can be curved. FIG. 3A shows the distributor plateas concave relative to the inlet pipe 37 and can be closer to the inletpipe (as shown by dashed lines) or closer to the feed pipes 38 (as shownin dashed lines). FIG. 3B shows the distributor plate as convex relativeto the inlet pipe 37 and can be closer to the feed pipes 38 (as shown insolid lines) or to the inlet pipe 37 (as shown in dashed lines).

The outlet header is not provided with a distributor.

In operation, gas enters the header. While some gas enters the coil orcoils 31A-31D adjacent to the inlet pipe 37, much of the gas flowstoward the ends of the header and into the associated coils (for example31E-31H). The coils, which are all the same size, all receive equalamounts of the gas. Thus, the heat exchanger operates more efficiently.

Although the distributor has been described in conjunction with anevaporative condenser as the preferred embodiment, it can also be usedwith other heat exchangers, such as coolers. The heat exchangerdescribed above can be used as a cooler. When used as a cooler, thedistributor is in the inlet header (which is now 35). Liquid enters theheader and encounters back pressure due to the distributor 51. Theliquid thus extends along the length of the header and enters the coils31 as spaced along the length of the header.

The foregoing disclosure and showings made in the drawings are merelyillustrative of the principles of this invention and are not to beinterpreted in a limiting sense.

1. A heat exchanger, comprising: a) an inlet header having a fluid inletand an interior cavity; b) an outlet header having a fluid outlet; c)heat exchange elements coupled to and in fluid communication with theinlet and outlet headers, the heat exchange elements comprising firstand second heat exchange elements, the first heat exchange elementcoupled to the inlet header at a first location, the second heatexchange element coupled to the inlet header at a second location, thefirst location being closer to the fluid inlet than is the secondlocation; d) a distributor located in the interior cavity of the inletheader between the fluid inlet and the heat exchange elements andextending between the first and second locations and the fluid inlet,the distributor causing back pressure for fluid entering the inletheader from the fluid inlet.
 2. The heat exchanger of claim 1 whereinthe distributor further comprises a perforated wall.
 3. The heatexchanger of claim 2 wherein the heat exchange elements comprise coils.4. The heat exchanger of claim 1 wherein the inlet header comprises apipe and the distributor comprises a perforated plate located in thepipe.
 5. An evaporative condenser, comprising: a) a condenser unit; b) awater sprayer located above the condenser unit; c) a fill sectionlocated below the condenser unit; d) a basin located below the fillsection; e) at least one fan for flowing air through the condenser unitand the fill section; f) the condenser unit comprising an inlet headerand an outlet header, the inlet header having a fluid inlet at a firstlocation, the inlet header having heat exchange elements at locationsother than the first location; g) a distributor in the inlet headerbetween the first and other locations, the distributor applying backpressure to fluid entering the inlet header from the fluid inlet.
 6. Theheat exchanger of claim 5 wherein the distributor further comprises aperforated wall.
 7. The heat exchanger of claim 6 wherein the heatexchange elements comprise coils.
 8. The heat exchanger of claim 5wherein the inlet header comprises a pipe and the distributor comprisesa perforated plate located in the pipe.
 9. The heat exchanger of claim 8wherein the perforated plate is flat.
 10. The heat exchanger of claim 8wherein the perforated plate is curved.